US Tax Help!

Just going to pile on to the million other questions with my own, as I cannot quite understand it all.   

No idea where to start with US taxes, but know I better figure it out soon, even if just to file for the extension. Here are my details:

Moved to the UK November 29, 2018
Husband had been with me in the US and was a green card holder
He surrendered his green card in January, but held it through the end of 2018
I did not work for the remainder of 2018 after arriving in the UK, but my husband began work for the UK entity immediately
We previously filed married filing jointly in the US
We had health insurance coverage through the end of November, then the NHS in December
I made a withdrawal of my 403b before leaving the US, which does carry a tax penalty that I need to pay and have not yet

All of my questions:
Where do I start/how do I file?
I understand we probably need an extension - do I need to pay the tax penalty from my 403b withdrawal before then?
What does the extension mean towards proving UK domicile?
Do I need to file an FBAR? (I opened a bank account in December, but it has not had more than $10k in it)
How do we avoid a health insurance penalty for December?
How do we present my husband's UK income for that last month toward US taxes?

Moving forward:
We moved from New York City. Anyone have any experience coming from there and proving UK domicile so as not to continue paying state/local taxes?
In 2019 (and beyond) will I still need to file with my husband? (He surrendered his green card, but we did file married/jointly for years before)

Also, I never paid for tax help in the US, and would prefer not to start now. However, I am not unwilling to explore that option, so if anyone has any place they could privately recommend to me, i'm all ears.

This should be fairly straightforward. (And yours is a unique situation which will dictate my following opinions.)

Moved to the UK November 29, 2018
He surrendered his green card in January, but held it through the end of 2018
I did not work for the remainder of 2018 after arriving in the UK, but my husband began work for the UK entity immediately
We previously filed married filing jointly in the US
Where do I start/how do I file?

IMO, file as married joint for 2018, somewhat similar** to your past filings.  (**exception to follow)
Going forward, since your husband abandoned his green card, you will have a decision to make for 2019 filing, but, for you, it would likely be married separate for 2019.

I understand we probably need an extension - do I need to pay the tax penalty from my 403b withdrawal before then?

Why? First, you have until 15 June to file since you will not be in the US on 15 April (or is it the 17th this year?).
BUT, any tax due (estimated payment) must be paid before 15 April to avoid a penalty, even if filing an extension.

What does the extension mean towards proving UK domicile?

Your husband already likely has UK domicile (if UKC).
You do not, and an extension for 2018 will have no bearing on 'domicile'. As for your UK 'residence' (if for FEIE, 2555 - physical presence/bona fide res.), which is something entirely different from domicile, by the time you file 2019 you should qualify if you remain abroad.
You did not have any foreign income during December, and have no need to claim FEIE for 2018.

Do I need to file an FBAR? (I opened a bank account in December, but it has not had more than $10k in it)

FBAR is an aggregate total of the maximum amount, at any time, in all foreign accounts over which you have signature authority during the tax year. Just your one account, or did you and your husband have an additional joint account(s)? There are other considerations besides 'bank' accounts.

We had health insurance coverage through the end of November, then the NHS in December

Check the IRS publications, but I believe there is a grace period of at least 1 month (perhaps 3?) a year during which you may not have insurance, and there is no penalty. Check to be sure.

I made a withdrawal of my 403b before leaving the US, which does carry a tax penalty that I need to pay and have not yet

Make a pre- 2018 return estimated payment before 15 April to avoid the penalty, as mentioned above.

How do we present my husband's UK income for that last month toward US taxes?

** the exception for 2018!
In your jointly filed return, include a form 1116, Foreign Tax Credit, which will based on the amount of tax withheld from your husband's UK pay for December 2018.

File as normal but include Form 1116, Schedule 6 to note your foreign (change of) address, Schedule 3 for transitioning 1116 to 1040, and be sure you file Schedule B and complete Part III.

Moving forward:
We moved from New York City. Anyone have any experience coming from there and proving UK domicile so as not to continue paying state/local taxes?

Others can comment on this, but I believe New York is a 'sticky' State, so you may need to terminate everything to do with NY from financial accounts to library cards.

In 2019 (and beyond) will I still need to file with my husband? (He surrendered his green card, but we did file married/jointly for years before)

Does your husband still want to be filing US tax returns on his UK income? There is a way, but most would avoid it with the USC filing MFS. It gives your husband a great deal of options for investment (and other freedoms) that he wouldn't have if filing MFJ with you.

Also, I never paid for tax help in the US, and would prefer not to start now. However, I am not unwilling to explore that option, so if anyone has any place they could privately recommend to me, i'm all ears.

If you've filed your own returns in the past, nothing for 2018 should be much different, with the exception of form 1116 FTC.

Good luck, although some may disagree with my comments (MFJ for 2018). Hopefully they will also respond.

One additional thought, was your husband a long term permanent resident of the US on his green card (8 tax years out of the last 15 - and any one day in a tax year qualifies as a full year). If so, that will alter things slightly.

Thank you so much, @theOAP! This is incredibly helpful.

A few more questions and answers for questions you asked:

My husband had his green card for just shy of two years.

Re: the FBAR and any other assets, we have no joint assets in the UK (for now).

Our only joint asset at all is currently a US bank account. We’d like to keep that open in case we ever move back, but for tax filing is it problematic down the line? It’s not like there is tons of money in it.

With regard to ceasing ties in NYC, would changing the address on bank accounts suffice, rather than closing them? The only other remaining tie I can think of is my voter registration, which I do not want to lose. I’ve changed our address on everything to the UK, and all other mail is being forwarded to my parents in Georgia, if that matters?

Re: domicile (or whatever) - it seems like I do not need to worry about this until I file for 2019, then?

@theOAP another question as I’ve been working on taxes... re: an extension.

Do I not need to file extensions until we have been physically present for 330 days in order to file for the foreign income tax credit? I ask because inputting my husband’s UK salary for that last month of 2018 significantly increases our tax liability. Or do we just have to suck it up, pay, and get the credit next year?

Regarding physical presence, just to confirm that means each day one is actually in the UK, discounting travel days and trips, etc. If that’s the case, we will have to put off filing until next December. Is that even possible?

My husband had his green card for just shy of two years.

Great, so after 2018, if you wish, he could be free from the US tax system (pending retirement accounts, etc.) and, most importantly, does not have to file Form 8854 for the Exit Tax.

Re: the FBAR and any other assets, we have no joint assets in the UK (for now).

Great. Did he not have any accounts in the UK, or elsewhere outside the US, during all of 2018? (Since he was a US Person during 2018, he has an FBAR obligation also).

Our only joint asset at all is currently a US bank account. We’d like to keep that open in case we ever move back, but for tax filing is it problematic down the line? It’s not like there is tons of money in it.

For the US, no problem at all.
For the UK, it's only a problem if there is interest paid during the UK tax year. The UK will tax worldwide income, but it's not really a problem other than declaring the interest for taxation.

With regard to ceasing ties in NYC, would changing the address on bank accounts suffice, rather than closing them? The only other remaining tie I can think of is my voter registration, which I do not want to lose. I’ve changed our address on everything to the UK, and all other mail is being forwarded to my parents in Georgia, if that matters?

Search the UK Yankee tax site for posts by vadio (perhaps if she see's this, she'll comment). Vadio has gone through an ordeal to break ties with another sticky State - Virginia. It will give you a feeling for all that's involved. Bank Accounts - ify; voter registration - ify, drivers license - ify, property ownership - slam dunk against you. I don't know, maybe others do, just how sticky New York and NYC are.

Re: domicile (or whatever) - it seems like I do not need to worry about this until I file for 2019, then?

Domicile is a very nebulous term. Taken to extremes, your domicile can be your father's birthplace.
To establish residence abroad for FEIE (Foreign Earned Income Exclusion), you need to have a permanent (tax) residence in the foreign country(s) for 330 days. From what you have said, you had no foreign earned income in 2018, so no FEIE or FTC required. For 2019, if you do have earned income, you will have 330 days abroad easily by the time you need to file the 2019 return, so, nothing to worry about. But, even more so (by the spring of 2020 when you'll file the 2019 return),  your residence abroad will encompasses a whole US calendar tax year and you may file as a bona fide resident of the UK for FEIE (no qualifying period required).

Do I not need to file extensions until we have been physically present for 330 days in order to file for the foreign income tax credit? I ask because inputting my husband’s UK salary for that last month of 2018 significantly increases our tax liability. Or do we just have to suck it up, pay, and get the credit next year?

Did you include form 1116 in the calculations?

FTC (Foreign Tax Credit) is completely different to FEIE. There is no qualifying period needed for the FTC. No 330 days. For FTC (Form 1116) you are simply saying "I made this amount of income from abroad, and I paid this amount of foreign tax on it to the foreign country. Please give me a credit on my US tax return for the foreign tax paid." According to the US/UK Tax Treaty, the US must honour the claim for credit since you are resident in the UK, and the UK has first rights of taxation on all income earned in the UK.

You'll be offsetting the tax due to the US by the tax your husband paid (December withholding) to the UK.
Edit to Add: FEIE excludes the foreign earned income from US taxation. The FTC includes all the foreign income (earned or unearned) on the US return, but then allows the tax paid to the foreign country to offset the US tax due on the foreign income on a dollar for dollar basis.

Regarding physical presence, just to confirm that means each day one is actually in the UK, discounting travel days and trips, etc. If that’s the case, we will have to put off filing until next December. Is that even possible?

Hopefully, you'll understand my (simplified) rambling attempts above to explain FEIE, and will realise, in your unique case, you won't need the physical presence test for either FEIE for 2018 (you'll be using FTCs for your husband's UK income) or in future years.

@theOAP thank you again!! This clarifies a lot more for me. I got mostly there today with my filing, but may be back for more questions in a bit!

I broke my ties with the Commonwealth of Virginia - which is notorious for holding onto you forever - after moving back to the UK in 2011. There was a specific process, forms to fill out, and a pile of supporting documentation to provide. Each state will be different, so the place to start is likely the Tax Commissioner (or equivalent) in NY.

I officially cancelled my voter registration in VA, but am still able to vote absentee. VA requires that any change of address be reported within 30 days for a driving license, and reporting a foreign address automatically cancels. That's an important point, as it was their first "admission" that I was no longer resident or domiciled there. I kept a bank account (and still have it), but changed to a UK address. I also had to prove that I owned no property, had no vehicles registered in VA, no kids in school, and a host of other ties (they even try to count a library card). It was basically proving that I had no ties, and no intent to return, which was easier as I had only lived in VA for 11 years, and was 67 at the time they finally got around to looking at all the documentation. It took over a year to get the official notice of change of domicile, but I persisted, and did it.

Keep the initial contact/questions short and sweet - say that you have moved to the UK, it's a permanent move, no intention to return to NY, and ask what you need to provide to confirm a "change of domicile".  It can be done.

Thanks everyone for your help when I first posted back in March. Perhaps inspired by Brexit, I got a little overwhelmed, filed an extension, and forgot about it all until this week.

I am back at it and wondering if anyone can direct me to more details on how one does back-reporting of FBAR :-/

Thanks everyone for your help when I first posted back in March. Perhaps inspired by Brexit, I got a little overwhelmed, filed an extension, and forgot about it all until this week.

I am back at it and wondering if anyone can direct me to more details on how one does back-reporting of FBAR :-/

An FBAR is not a tax return. The FBAR for 2018 is not late. For delinquent or incomplete FBARs for earlier years, the IRS offer a choice of the SFOP or the delinquent FBAR procedures.